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Pathogenesis of Bacterial Infection Normal Human Microbiota Bacterial Genetics Sterilization and Disinfection Aseptic Technique and Staining...

Pathogenesis of Bacterial Infection Normal Human Microbiota Bacterial Genetics Sterilization and Disinfection Aseptic Technique and Staining Sensitivity Testing Water Analysis Dean Frederick R. Llanera, MD, MSMT, RMT, FPSP Pathologist, Residents & Interns’ Training Officer, Philippine Heart Center Dean, College of Medical Laboratory Science, De La Salle Medical and Health Sciences Institute Tropical Medicine Training & Guest Lecturer, University of Minnesota Past Board of Examiners, Philippine Society of Pathologists Former Tenured Faculty, University of Santo Tomas  Learning Objectives: Pathogenicity of Bacterial Infection and Normal Flora To review the basic concepts on the infectious process To know the virulence factors exert their mechanisms To be familiar with the common bacterial virulence factors To differentiate resident from transient microbiota To have an overview of the normal human flora present in various sites of the body  Characteristics of Pathogenic Bacteria Transmissibility Adherence to Host Cells Persistence Invasion of host cells and tissues Toxigenicity Ability to evade or survive the host’s immune system  Important Terms Adherence, Adhesion Virulence or Attachment Toxigenicity Carrier Superantigens Infection – Protein toxins that Invasion active the immune system by binding to Microbiota MHC & TCRs and Pathogenic stimulate many T cells – True to produce massive quantities of cytokines – Opportunistic  Adherence (adhesion, attachment): The process by which bacteria stick to the surfaces of host cells. After bacteria have entered the body, adherence is a major initial step in the infection process. The terms adherence, adhesion, and attachment are often used interchangeably.  Carrier: A person or animal with asymptomatic infection that can be transmitted to another susceptible host Infection: Multiplication of an infectious agent within the body. Multiplication of the bacteria that are part of the normal microbiota of the gastrointestinal tract, skin, and so on is generally not considered an infection; on the other hand, multiplication of pathogenic bacteria (eg, Salmonella species)—even if the person is asymptomatic—is deemed an infection.  Invasion: The process whereby bacteria, animal parasites, fungi, and viruses enter host cells or tissues and spread in the body. Microbiota: Microbial flora harbored by normal, healthy individuals. Nonpathogen: A microorganism that does not cause disease; may be part of the normal microbiota.  Opportunistic pathogen: An agent capable of causing disease only when the host’s resistance is impaired (ie, when the patient is “immunocompromised”). Pathogen: A microorganism capable of causing disease. Pathogenicity: The ability of an infectious agent to cause disease.  Superantigens: Protein toxins that activate the immune system by binding to major histocompatibility complex (MHC) molecules and T-cell receptors (TCR) and stimulate large numbers of T cells to produce massive quantities of cytokines. Toxigenicity: The ability of a microorganism to produce a toxin that contributes to the development of disease.  Virulence: The quantitative ability of an agent to cause disease. Virulent agents cause disease when introduced into the host in small numbers. Virulence involves adherence, persistence, invasion, and toxigenicity  Koch’s Postulates 1. The microorganism should be found in all cases of the disease & its distribution in the body should be where the lesions are. 2. The microorganism should be grown in pure culture in vitro for several generations. 3. If the pure culture is inoculated into a susceptible host, the typical disease must result 4. Organism can be reisolated from # 3.  Transmission of Infection Overcoming barriers / lines of defnese Manner of transmission – Portals of entry  The Infectious Process Attachment Multiplication Spread – Bacteremia (transient or persistent)  Genomics & Bacterial Pathogenicity Mobile Genetic Elements – Plasmids, Transposons & Bacteriophages Pathogenicity Islands – Large groups of genes that are associated with pathogenicity & are located in the bacterial chromosome  Regulation of Bacterial Virulence Factors Transduction Temperature & pH dependent virulence factors Osmolality & amino acid composition Virulence plasmid-encoded proteins Bacterial motility  Bacterial Virulence Factors Adherence Factors- pili, fimbriae Invasion of Host cells and tissues Toxins –exotoxin vs. endotoxin Table 9-4 Enzymes – collagenase, hyaluronidase, IgAse, streptokinase Antiphagocytic factors - capsule Intracellular pathogenicity – resistance to lysosmes Antigenic heterogeneity – on bacterial surface, O, H Bacterial secretion system - for gram negs Fe requirement – effect of IDA. Biofilms – persistent & difficult to treat Figure 4.8  Normal Human Microbiota First line of defense against microbial pathogens Assist in digestion Role in toxin degradation Contribute to maturation of the immune system Shift in flora – Bacterial Vaginosis  Human Microbiome Project Use of 16S rRNA gene sequencing – Mouth – Esophagus – Stomach – Colon – Vagina Role of the Resident Microbiota Resident microbiota – Fixed types of organisms regularly found in a given area at a given age; if disturbed, it promptly restablishes itself Transient microbiota – Nonpathogenic or potentially pathogenic organisms that inhabit the skin or mucous membranes for hours, days or weeks – Derived from the environment, does not produce disease nor establish itself permanently on the surface; opportunistic  Normal Microbiota of: Skin Mouth & Upper Respiratory Tract Intestinal Tract Urethra Vagina Conjunctiva  Skin Eliminate nonresident organisms – Low pH – Fatty acids in the sebaceous secretions – Presence of lysozyme Physical & Immunologic barrier  Mouth & Upper Respiratory Tract Considerable diversity in the saliva microbiome Dental plaque - biofilm  Intestinal Tract At birth – the intestine is sterile, organisms are soon introduced with food. Determinants of early flora: maternal vaginal, fecal, skin microbiota Normal acid pH of stomach Colon of normal adult: 96-99 % of the resident bacterial flora are anaerobes  Intestinal Tract - Functions Protective – resident bacteria displace and inhibit potential pathogens indirectly by competing for nutrients & receptors or directly by production of antimicrobial factors such as bacteriocins & lactic acid Commensals are needed for the development of the mucosal immune system Metabolic functions – synthesis of Vitamin K, biotin, folate, and enhance ion absorption  Intestinal tract Pseudomembranous colitis Antibiotic associated Fecal microbiota transplantation (FMT) – stool transplant – for those with infection with Clostridium difficile  Urethra Anterior urethras of both sexes contain organisms found on the skin and perineum.  Vagina Lactobacillus acidophilus / Doderlein’s bacillus Gardnerella vaginalis – Bacterial vaginosis  Conjunctiva Conjunctival flora is normally held in check by the flow of tears, which contain antibacterial lysozyme. Bacterial Genetics  Nucleic Acid Structure and Organization 1. DNA –deoxyribonucleic acid 2. RNA- ribonucleic acid DNA – consists of deoxyribose sugars connected by phospodiester bonds bases are covalently linked to each deoxyribose sugar  Purine bases- adenine and guanine Pyrimidine bases- cytosine and thymine In RNA, uracil replaces thymine Nucleotide – sugar, phosphate, base  DNA and RNA are nucleotide polymers and the order of bases along a DNA or RNA strand is known as the base sequence. This sequence provides the information that specifies the proteins that will be synthesized by microbial cells.  Three major types of RNA 1. mRNA 2. tRNA 3. rRNA  RNA is a nucleic acid that can be divided into three main types: Messenger RNA (mRNA) – transcribed copy of DNA Ribosomal RNA (rRNA) – found in ribosomes and is involved translation of mRNA to protein Transfer RNA (tRNA) – carries amino acids to ribosome for translation of mRNA to protein Image: https://ib.bioninja.com.au/standard-level/topic-2-molecular-biology/26-structure-of-dna-and-rna/types-of-rna.html  Genes and the Genetic Code A DNA sequence that encodes for a specific product (RNA or protein) is defined as a gene. All genes taken together within an organism comprise that organisms genome.  The Bacterial Chromosomes The bacterial chromosomes contains all genes essential for viability and exists as a double stranded, closed circular, naked macromolecule. The molecule is extensively folded and twisted (i.e. supercoiled) so that it may be accomodated within the bacterial cell.  Non Chromosomal Elements of the Genome 1. Plasmids- able to replicate and encode information for the production of various cellular products. - not as stable as the chromosome and maybe lost during cellular replication Plasmid genes do not usually encode for products essential for viability.  Non Chromosomal Elements of the Genome 2. Transposable elements- are pieces of DNA that move from one genetic element to another, from plasmid to chromosome or vice versa.  Transposable Elements These extra chromosomal elements play a key role in the exchange of genetic material throughout the bacterial microbiosphere, including genetic exchange among clinically relevant bacteria.  Replication Four stages 1. Unwinding or relaxation of the chromosome 2. Unzipping or disconnecting the complementary strands of the parental DNA 3. Synthesis of the new DNA strands 4. Termination of replication with release of two identical chromosomes  Transcription DNA expression begins with transcription which converts the DNA base sequence of the gene into a messenger RNA that is complementary to the gene’s DNA sequence.  Transcription In mRNA thymine is replaced with uracil In bacteria the mRNA that result from the transcription process are polysictronic, that is they encode for several gene products. The transcription process not only produces mRNA but also tRNA.  Translation By this process the genetic code within mRNA is translated into specific amino acid sequences that are responsible for protein structure, and hence, function.  Genetic Exchange and Genetic Diversity Genetic exchange in bacteria is accomplished by three basic mechanisms: 1. Mutation 2. Genetic Recombination 3. Gene exchange between bacteria, with or without recombination  Mutation Is defined as a change in the original nucleotide sequence of a gene or genes within an organism’s genome. Mutation may arise spontaneously, perhaps by an error made during DNA replication.  Mutation Mutations may be induced by chemical or physical factors in the environment or by biological factors such as introduction of foreign DNA into the cell.  Genetic Recombination In this process some segment of DNA that originated from one bacterial cell (i.e., donor) enters a second bacterial cell (i.e. recipient) and is exchanged with a DNA segment of the recipients genome.  Genetic Recombination Also referred as homologous recombination because the pieces of DNA that are exchanged usually have extensive homology or similarities in their nucleotide sequences.  Gene Exchange 1. Transformation 2. Transduction 3. Conjugation  Transformation Involves recipient cell uptake of free DNA released into the environment when another bacterial cell dies and undergoes lysis. Certain bacteria are able to take up this free DNA, that is able to undergo transformation. Such bacteria are said to be competent. Ex. Haemophilus, Streptococcus and Neisseria  Transformation The mixing of DNA between bacteria via transformation and recombination plays a major role in the development of the antibiotic resistance and in the dissemination of genes that encode factors essential to an organism’s ability to cause disease.  Transformation Additionally, gene exchange by transformation is not limited to organisms of the same specie.  Transduction This process is mediated by viruses that infect bacteria (bacteriophages). These viruses integrate their DNA into the bacterial cell’s chromosome. When viral products is completed, viral DNA is excised from the bacterial chromosomes.  Conjugation This process occurs between two living cells, involve cell to cell contact, and require mobilization of the donor’s bacterium chromosome. In E.coli contact is mediated by a sex pilus What is the name of the process shown? Elaborate on the steps of the process. Conjugation The donor cell produces a pilus, which is encoded by the plasmid, and contacts a potential recipient cell that does not contain the plasmid. Retraction of the pilus brings the cells into close contact, and a pore forms in the adjoining cell membranes. Formation of the mating pair signals the plasmid to begin transfer from a singlestranded nick at oriT. The nick is made by plasmid-encoded tra functions. The 5 end of a single strand of the plasmid is transferred to the recipient through the pore. During transfer, the plasmid in the donor is replicated, its DNA synthesis being primed by the 3 OH of the oriT nick. Replication of the single strand in the recipient proceeds by a different mechanism with RNA primers. Both cells now contain double-stranded plasmids, and the mating pair separates. What bacterial surface structure is required for the process shown to occur? The F or sex pilus is required for conjugation to occur. What are the distinguishing characteristics of this horizontal gene exchange mechanism compared to the two other common mechanisms? Site an example of a bacterial trait that can be transferred through this mechanism. In contrast to the two other common exchange mechanisms, conjugation requires cell-to-cell contact and would be inhibited if the donor and recipient cells were separated by a membrane. Conjugation is resistant to DNase treatment. Antimicrobial resistance can be transferred via conjugation. What process is shown? Generalized transduction What process is shown? Elaborate the process and describe the differences between the 2 processes. Specialized transduction. In generalized transduction, only pure bacterial DNA is transferred as compared to specialized transduction. GT occurs during lytic phase, while ST occurs during lysogenic phase. Temperate bacteriophage is present in ST. ST rarely occurs compared to GT.  GENERALIZED VS. SPECIALIZED 1. bacterium. TRANSDUCTION A virulent (lytic) bacteriophage infects a 1. A temperate bacteriophage infects a bacterium. 2. Viral DNA integrates into bacterial chromosome 2. The phage genome enters the bacterial cell. and becomes the prophage stage 3. Virus governs the bacterial metabolic 3. Viral DNA remains within bacteria for several mechanisms to make its own DNA and other generations necessary components and enzymes. 4. Upon a spontaneous induction, viral DNA 4. Bacterial DNA hydrolyses into small pieces. detaches the bacterial chromosomal DNA. 5. Genetic material packs inside the new phages. 5. Fragments of bacterial DNA detach from the Occasionally bacterial DNA fragments pack in bacterial chromosome with viral DNA. new phage capsids 6. Viral DNA replicates together with bacterial 6. Bacterial cell lyses and releases the new genes and package inside new capsids and phages. make new phages. 7. When transduced phage infects another 7. Bacterial cell lyses and releases the new bacterium, the previous bacterial DNA phages. incorporates into a new. 8. New phages infect new bacteria. 9. Bacterial DNA mixes with new bacteria during the infection. Identify the type of gene transfer. Describe the process. Transformation Transformation can define as the process of taking up of an extracellular or free DNA strand of one bacterial cell (donor’s cell) by the competent bacterial cell (recipient’s cell). The taking up of the DNA strand occurs either by natural or artificial means. What characteristic must the recipient bacterial cell express for this process to occur? The recipient bacterial cell must express competence for transformation to occur. What are the characteristics that distinguish this horizontal gene exchange mechanism from the two other most common mechanisms? In contrast to the two other most common gene exchange mechanisms, transformation is sensitive to the presence of DNase and does not require cell-to-cell contact.  Applications of Molecular Diagnostics Nucleic Acid Hybridization Techniques – Formats: Blotting Techniques Nucleic Acid Amplification – PCR Strain Typing and Identification  Within our cells, we have chromosomes found inside the nucleus. The DNA strands are compacted as chromosomes. Image from Wikipedia: https://en.wikipedia.org/wiki/Chromosome  DNA is a nucleic acid molecule in the form of a double-stranded helix. Each strand of DNA is STABLE composed of 4 types of nitrogen bases – adenine, cytosine, guanine and thymine. The double stranded helix is the most energetically favorable state of DNA. It’s so stable that it needs extremes of heat, pH or by use of destabilizing agents to lose its conformation. Image: Yoon, Byung-Jun. (2007). Signal processing methods for genomic sequence analysis.  DNA contains our genetic information. DNA is transcribed to RNA transcription translation and then translated to proteins. DNA RNA Protei Some viruses have reverse transcription n reverse transcriptase that allows reverse transcription of DNA from RNA. Image from: https://ib.bioninja.com.au/standard-level/topic-2-molecular-biology/27-dna-replication-transcri/central-dogma.html  RNA is a nucleic acid that can be divided into three main types: Messenger RNA (mRNA) – transcribed copy of DNA Ribosomal RNA (rRNA) – found in ribosomes and is involved translation of mRNA to protein Transfer RNA (tRNA) – carries amino acids to ribosome for translation of mRNA to protein Image: https://ib.bioninja.com.au/standard-level/topic-2-molecular-biology/26-structure-of-dna-and-rna/types-of-rna.html  DNA Parent strands A T A Replicatio A C T G A C n The two double stranded DNA duplication uses DNAs are exactly the same each strand of the T A T as the parent DNA. parent DNA to G C G synthesize daughter strands. T A T The products are composed of a parent strand and Daughter strands a daughter strand.  DNA RNA DNA vs A A T T A A RNA RNAdiffers DNA is lessfrom DNA, not only stable RNA than because in it is composition, structure and C G C single stranded but also function. because 1. DNA isthe hydroxyl double stranded, T A T U group (-OH) while RNA predisposes is single G C G susceptibility stranded. from alkaline hydrolysis. T A T U 2. In RNA, thymine is replaced by uracil. 3. The sugar in DNA is deoxyribose, while the sugar in RNA is ribose containing hydroxyl group.  Though DNA replication is conceptually simple, the process is complex and involves a number of accessory proteins and enzymes. This video explains the details of DNA replication. Animation by Polymime Animation Company Ltd.  Unwindi ng the DNA Extreme heat, hydrogen bond disrupters and pH outside 4-9 can unwind the DNA. Because temperature is often used to unwind Heat DNA, the process has been referred to as pH 4-9 melting. Hydrogen bond disrupters  The temperature A T at which 50% of C G dsDNA is converted into single stranded % helix 50% MELTING POINT DNA is called the melting Temperature point. The melting point depends  Polymerase Chain Reaction Thermocycler, an equipment that raises and lowers PRIMER POLYMERASE NUCLEOTIDES temperature Polymeraseofchain the sample reactionin cycles, (PCR) isis avery important laboratory in this technique process. based on the process of DNA replication. The three main steps of PCR COOL (40-70 HEAT HEAT °C) (94°C) (70-75°C) are: Basically, 1. PCR consists Denaturation of: of - unwinding 1. strands Target DNA through- from heat specimen Primers – complementary 2. Annealing 2. –attachmenttoofthe sequenceto primer of the thetarget strand target segment 3. through Taq polymerase a cooler - DNA polymerase from a hotspring bacteria temperature 4. Nucleotides - 3. Extension – addition of deoxyribonucleotide triphosphates nucleotides to the primer Image from Mike Powers Illustration & Design: http://www.mikepowers-illustration.com/projects/2016/11/22/information-science with a warm temperature  PCR allows nucleic acid amplification or production of multiple copies of a target Target DNA DNA segment called amplicons. With large number of DNA copies, the presence of a target DNA segment is easier detected. After the PCR amplification, the specific amplicons may be detected using various methods such as electrophoresis.  Reverse Transcriptase PCR (RT-PCR) If the target is an RNA, a complementary Reverse Transcript DNA (cDNA) ion is first produced by reverse transcription. Reverse transcriptase synthesizes the cDNA using RNA as template. Double stranded DNA is produced and PCR amplification proceeds in the usual manner. This process is called reverse-transcriptase  Real Time PCR (qPCR) Real-Time or Quantitative Target DNA PCR (qPCR) is a variation to PCR that combines amplification and detection in one step. The amplicons are detected AMPLIC as they are made in real- ONS time. Fluorescent signal is CYCL incorporated into the ES amplicon and detected using a specialized thermocycler.  The amplicons created per cycle may be detected by POLYMERA using a fluorescent dye or SE S fluorescent probe. Y B R Fluorescent dye such as SYBR green I preferentially binds to double stranded F DNA. TaqMan probes are labeled POLYMERA Probe SE with a fluorophore and Prime quencher. r The probe attaches to the target sequence. Polymerase cleaves off the fluorophore resulting to fluorescence.  AMPLIFICATION PLOT With real-time PCR, special A sigmoid fluorescentcurve is generated threshold can be thermocycler with precision and is composed set above of different the baseline to call optics measures emitted EXPO PLA phases: POSITIVE samples. BASEL fluorescence. 1. Baseline or lag phase – NENTI TEA A computer software monitors FLUORES INE C Cycleonlythreshold background (Ct)signal is or cycle t AL U the fluorescence at every observed (Cq) is the number quantification CENCE Fluorescence threshold cycle and generates an INTENSIT 2. Exponential of cycles neededphase – to overcome amplification plot. Y the amplification fluorescenceisthreshold observedor This plot shows the and fluorescence background noise. exceeds fluorescence intensity background noise PCR versus PCR cycle number. 3. Plateau phase – reactants CYCLES become rate limiting and amplicon accumulation sto  Conventional PCR Real-time PCR Two-steps One-step Amplification Combined amplification and detection Post-amplification detection (electrophoresis) (fluorescence) Post-amplification analysis needed: NO post-amplification analysis: → more time needed → faster → open system: prone to contamination → closed system (reaction tubes remain closed) → may lead to false positives → less risk for contamination → More specific Increased specificity with the use of probes Qualitative to semi-quantitative Quantitative → More reproducible → Generates amplification plot and standard cruve , Melting point analysis feasible Figure 11.1 Figure 11.5  Pasteurization Used to disinfect beverages Heat is applied to liquids to kill potential agents of infection and spoilage, while retaining the liquid’s flavor and food value Special heat exchangers – Flash method: expose to 71.6°C for 15 seconds – Batch method: expose to 63°C to 66°C for 30 minutes Does not kill endospores or thermoduric microbes  Boiling Water For disinfection and not sterilization Expose materials to boiling water for 30 minutes  Dry Heat: Hot Air and Incineration Incineration – Ignites and reduces microbes to ashes and gas – Common practice in microbiology lab- incineration on inoculating loops and needles using a Bunsen burner – Can also use tabletop infrared incinerators Figure 11.6  Dry Oven Usually an electric oven Coils radiate heat within an enclosed compartment Exposure to 150°C to 180°C for 2 to 4 hours Used for heat-resistant items that do not sterilize well with moist heat Modes of Action of Ionizing Versus Nonionizing Radiation Ionizing radiation: if the radiation ejects orbital electrons from an atom causing ions to form Nonionizing radiation: excites atoms by raising them to a higher energy state but does not ionize them Figure 11.7  Ionizing Radiation: Gamma Rays, X Rays, and Cathode Rays Cold sterilization Dosage of radiation- measured in Grays Exposure ranges from 5 to 50 kiloGrays Gamma rays, most penetrating; X rays, intermediate; cathode rays, least penetrating  Applications of Ionizing Radiation Food products Medical products  Nonionizing Radiation: Ultraviolet Rays Wavelength approximately 100 nm to 400 nm Germicidal lamp: 254 nm Not as penetrating as ionizing radiation Powerful tool for destroying fungal cells and spores, bacterial vegetative cells, protozoa, and viruses Figure 11.9 Applications of Ultraviolet Radiation Usually disinfection rather than sterilization Hospital rooms, operating rooms, schools, food prep areas, dental offices Treat drinking water or purify liquids  MIC To be effective, the clinically obtainable antibiotic concentration in body fluids should be greater than the MIC.  McFarland 99.5 mL of 1 % sulfuric acid 0.5 mL of 1.175 % barium chloride 1.5 x 10 (8) CFU/mL Broth Macrodilution (Tube Dilution) Impractical to use routinely when several antimicrobial agents must be tested on an isolate or if several isolates must be tested Can be used when MBC endpoints are to be subsequently determined  Broth Microdilution Tests Multiwell microdilution tests  Agar Dilution Tests Specific volumes of antimicrobial solutions are dispensed into premeasured volumes of molted an cooled agar, which is subsequently poured into standard Petri dishes MHA with sheep’s blood for fastidious bacteria  Disk Diffusion Kirby Bauer 150 m diameter – 12 disks Oxacillin (Methicillin) Resistance Cefoxitin – to induce greater expression of PBP2a in mecA containing strains of staphylococci and also functions as a test reagent to detect resistance  ESBL Resistance to ampicillin because of production plasmid-mediated Beta lactamase known as TEM-1 and SHV-1  Special Antimicrobial Susceptibility Tests MIC / MBC Time – kill assays – bactericidal activity of antimicrobial agents Synergy Tests – synergism, antagonism, indifference Serum Bactericidal Test – amount of antimicrobial agent and other factors (antibody, opsonin, complement) present Molecular Probes  Infectious Diseases Types of Infection – Primary/secondary; acute/chronic; localized / generalized; focal/systemic; recurrent, latent, overt, nosocomial, idiopathic, iatrogenic, asymptomatic / inapparent / subclinical Phases in the Course of Infection Epidemic, Endemic, Sporadic, Pandemic Host-Microbe Relationship Bacteremia / SIRS Pathogenicity & Virulence  Specimen Collection Blood, urine, CSF, aspirated (synovial), sputum, feces, throat swab, rectal swab, nasal swab, eye/ear discharge, urethral smear  Preservation Refrigerate Room Temp – CSF for viruses – CSF for bacteria – Ear : outer – Ear : inner – Catheter tip (IV) – Abscess, lesion, – sputum wound – Body fluids – Genital – Nasal, NP, throat – tissue  Specimen Priority 1 – critical / invasive – amniotic fluid, blood, brain, CSF, heart valves, pericardial fluid 2 – unpreserved – body fluids not in Level 1, bone, drainage from wounds, feces, sputum, tissue 3 – quantitation required – catheter tip, urine, tissue for quantitation 4 – preserved (not for Bacteriology) – feces in preservative; urine in preservative; swabs in holding medium (aerobic & anaerobic)  Biosafety Levels 1 – standard teaching labs – Micrococcus, Lactobacillus, Saccharomyces 2 – moderate potential to infect – Staph, enterics, Corynebacterium, helminths, Hepa A, B, rabies , Cryptococcus, Blastomyces 3 – severe/lethal if inhaled – M.tb, F. tularensis, Y. pestis, Brucella, C. burnetti, C. immitis, yellow fever, WEE, AIDS 4 – highly virulent when inhaled – flavi,  Gram Positive Cocci (Aerobic) Catalase + – Staphylococcus – Micrococcus Catalase – – Streptococcus, Enterococcus, Leuconostoc, Lactococcus, Clobicatella, Pediococcus, Aerococcus, Gemella, Helcococcus, Alloiococcys otitidis  Gram Positive Bacilli (Aerobic) Branching – Nocardia (partially acid fast), Streptomyces, Rhodococcus, Oerskovia Non Branching – Catalase Positive Bacillus, Brevibacillus, Paenibacillus, Listeria Corynebacterium – Catalase Negative Erysipelothrix, Actinomyces, Arcanobacterium, Bifidobacterium, Gardnerella Gram Negative Cocci (Aerobic) Neisseria Moraxella Gram Negative Bacilli/Coccobacilli (Aerobic) McConkey Agar Growth – Oxidase (-): Enterobacteriaceae, Acinetobacter, Stenotrophomonas – Oxidase (+): Pseudomonas, Burkholderia, Achromobacter, Rhizobium, Ochrobactrum, Chyseobacterium, Sphingobacterium, Alcaligenes, Bordetella (non pertussis), Comamonas, Vibrio, Aeromonas, Plesiomonas, Chromobacterium McConkey Agar No Growth Growth Require Special Media Gram Negative Bacilli/Coccobacilli (Aerobic) McConkey Agar Growth McConkey Agar No Growth – Oxidase variable : Haemophilus – Oxidase + : Sphingomonas paucimobilis, Moraxella, Neisseria elongata, Eikenella corrodens, Weeksella virosa, Pasturella, Suttonella, Mannheimia haemolytica, Actinobacillus, Kingella, Cardiobacterium, Capnocytophaga Growth Require Special Media Gram Negative Bacilli/Coccobacilli (Aerobic) McConkey Agar Growth McConkey Agar No Growth Growth Require Special Media – Bartonella, Afipia, Campylobacter, Arcobacter, Helicobacter, Legionella, Brucella, Bordetella pertussis, Bordetella parapertussis, Franciscella, Streptobacillus moniliformis, Sprillum minus Not characterized by Gram reaction Mycobacterium Obligate intracellular and nonculturable bacteria – Rickettsia – Chlamydia Cell wall deficient bacteria – Mycoplasma – Ureplasma Spirochetes  Anaerobic Bacteria Gram Positive Anaerobic Cocci – Collinsella aerofaciens, Finegoldia magna, Micromonas micros, Peptococcus niger, Peptostreptococcus anaerobius, Schleiferella asaccharolytica, Atopobium, Anaerococcus Gram Positive Anaerobic Bacilli Gram Negative Anaerobic Cocci Gram Negative Anaerobic Bacilli  Anaerobic Bacteria Gram Positive Anaerobic Cocci Gram Positive Anaerobic Bacilli – Propionibacterium, Actinomyces, Clostridium, Bifidobacterium, Eggerthella lenta, Eubacterium, Lactobacillus, Mobiluncus Gram Negative Anaerobic Cocci Gram Negative Anaerobic Bacilli  Anaerobic Bacteria Gram Positive Anaerobic Cocci Gram Positive Anaerobic Bacilli Gram Negative Anaerobic Cocci – Veilonella parvula Gram Negative Anaerobic Bacilli – Bacteroides, Fusobacterium, Bilophila wadsworthia, Leptotrichia, Porphyromonas, Prevotella Gram Stain Initial / primary stain – crystal violet Mordant – Gram’s iodine Decolorizer 95 % ethanol Counterstain/sec stain - safranin Acid Fast Stain – cold (Kinyoun) & hot (Ziehl Neelsen) Mycolic acid Cord factor Sulfatides Partially acid fast - Nocardia Medical Microbiology & Pharmacology of Anti-Infective drugs I. APPROACH TO TREATMENT OF INFECTIOUS DISEASE Evaluate evidence supporting an infection (signs & symptoms) EXS: fever, malaise, swollen lymph nodes, leukocytosis, diarrhea, prolonged cough Evaluate the potential of confounding variables EXS: drug fever, autoimmune disorders Determine the most likely site of infection by focusing on signs & symptoms & the pathogens commonly associated with specific sites of infection (refer to Table 1) Identify pathogens (exs: Gram’s stain, cultures, diagnostic tests) Empiric therapy Directed Therapy I. APPROACH TO TREATMENT OF INFECTIOUS DISEASE Empiric therapy Directed Therapy Early intervention for life- Determine susceptibility of threatening diseases: pathogens to specific history, physical exam, antimicrobials clinical experience Choose agent based on Choose agent based on pathogen, patient & patient & infection infection Clinical efficacy, ADR & PK profile, cost Monitor & modify based on patient response (efficacy & toxicities) II. CLASSIFICATION OF ANTIMICROBIAL DRUGS 3 Schemes: 1. Effects on cells : 1.1 Bactericidal – drugs that actually kill microorgs (bacteria)  for immediately life-threatening : patients with PMLs < 500/uL  endocarditis (phagocytosis is limited)  EXS: aminoglycosides,penicillins, quionolones, cycloserine, vancomycin, carbapenems 1.2 Bacteriostatic – drugs that inhibit bacterial growth but does not kill them  host defense mechanisms (phagocytosis) are required to kill the bacteria  EXS: chloramphenicol, nitrofurantoin, clindamycin, tetracycline, erythromycin, trimethoprim, lincomycin, sulfonamides II. CLASSIFICATION OF ANTIMICROBIAL DRUGS 3 Schemes: 2. Range of Activity : 2.1Broad-spectrum antibiotics – active against a wide variety of microorganisms  EXS: tetracycline – active vs g- rods: chlamydias, mycoplasmas, rickettsias chloramphenicol – all bacteria except Mycobacteria & Pseudomonas sp 2.2 Narrow-spectrum antibiotics – active against a particular group of microorganisms  EXS:erythromycin – active vs g+ Actinomyces, Corynebacterium Bacillus, Clostridium vancomycin – active vs g+ cocci: staphylococci & enterococci II. CLASSIFICATION OF ANTIMICROBIAL DRUGS 3 Schemes: 3. Sites of Action : affect the integrity or synthesis II. CLASSIFICATION OF ANTIMICROBIAL DRUGS A. ANTIBACTERIAL DRUGS B. ANTIFUNGAL DRUGS 1. Cell-wall synthesis inhibitors & β-lactamase inhibitors Carba- β- Penicillins Cepha- penems & Others Lactamase losporins Mono- inhibitors bactams Natural 1st Generation Imipenem, Vancomycin Clavulanic Cilastatin acid Antistaphy- 2nd Generation Aztreonam Cycloserine Sulbactam lococcal Amino- 3rd Generation Isoniazid Tazobactam penicillins Antipseudo 4th Generation -monal >> bactericidal; cell wall contains peptidoglycan II. CLASSIFICATION OF ANTIMICROBIAL DRUGS 1. Cell-wall synthesis inhibitors & β-lactamase inhibitors UDP-acetylglucosamine TRANSPEPTIDATION II. CLASSIFICATION OF ANTIMICROBIAL DRUGS 1. Cell-wall synthesis inhibitors & β-lactamase inhibitors 1.1 PENICILLINS Natural Antistaphylo- Aminopeni- Antipseudo- Penicillins coccal cillins monal Penicillins Penicillins Penicillin G Methicillin Ampicillin Mezclocillin Penicillin V Nafcillin Amoxicillin Piperacillin Pen G Oxacillin Azlocillin procaine Pen G Dicloxacillin Carbenicillin benzathine Cloxacillin Ticarcillin II. CLASSIFICATION OF ANTIMICROBIAL DRUGS 1. Cell-wall synthesis inhibitors & β-lactamase inhibitors 1.1 PENICILLINS STRUCTURE: S N O COOH Natural MOA: block transpeptidation of peptidoglycan Penicillins USES: g+, g-, spirochetes, anaerobes Pneumonia – Strep pneumoniae Pharyngitis, scarlet fever – Strep pyogenes Penicillin G Syphilis - Treponema pallidum Meningitis -Neisseria meningitidis Penicillin V Diphtheria - Corynebacterium diphtheriae Anthrax - Bacillus anthracis Pen G gas gangrene – Clostridium perfringens procaine DRAWBACKS & SIDE EFFECTS: Pen G widespread resistance; hypersensitivity benzathine rxns; diarrhea; seizures with renal probs. ADMN : Pen V = oral admn; others = IV, IM II. CLASSIFICATION OF ANTIMICROBIAL DRUGS 1. Cell-wall synthesis inhibitors & β-lactamase inhibitors 1.1 PENICILLINS Penicillinase - Resistant Penicillins Antistaphylo- MOA: inhibitors of cell wall synthesis coccal Penicillins USES: narrow spectrum (penicillinase producing Staphylococci); not for g- Methicillin DRAWBACKS & SIDE EFFECTS: Nafcillin Methicillin – interstitial nephritis Oxacillin - hepatotoxic Oxacillin NOTES: methicillin & dicloxacillin = most resistant Dicloxacillin to β-lactamases Cloxacillin Nafcillin = best with renal failure Vancomycin = given to those with methicillin-resistant S. aureus II. CLASSIFICATION OF ANTIMICROBIAL DRUGS 1. Cell-wall synthesis inhibitors & β-lactamase inhibitors 1.1 PENICILLINS Extended – Spectrum Penicillins MOA: inhibitors of cell wall synthesis USES: g+ (Streptococcus, Staphylococcus, Aminopeni- Enterococcus, Clostridium) & g- (E. coli, H. cillins influenzae, H. pylori, Salmonella);URTI & LRTI;UTI ; gastroenteritis Ampicillin DRAWBACKS & SIDE EFFECTS: inactivated by β-lactamase Amoxicillin NOTES: can be combined with β-lactamase inhibitors II. CLASSIFICATION OF ANTIMICROBIAL DRUGS 1. Cell-wall synthesis inhibitors & β-lactamase inhibitors 1.1 PENICILLINS Extended – Spectrum Penicillins Antipseudo- MOA: inhibitors of cell wall synthesis monal USES: g- (serious Pseudomonal infections) Penicillins Mezclocillin DRAWBACKS & SIDE EFFECTS: Piperacillin inactivated by β-lactamase Azlocillin NOTES: can be combined with β-lactamase Carbenicillin inhibitors Ticarcillin II. CLASSIFICATION OF ANTIMICROBIAL DRUGS 1. Cell-wall synthesis inhibitors & β-lactamase inhibitors 1.2 β-Lactamase Inhibitors “Suicide Inhibitors” MOA: bind to & inactivate β-Lactamase β-Lactamase USES: extend the spectrum of other β-lactam inhibitors agents (g+ S.aureus, g- H. influenzae & anaerobes Bacteroides fragilis) Clavulanic acid NOTES: Sulbactam Amoxicillin + Clavulanic acid = Augmentin Ticarcillin + Clavulanic acid = Timentin Tazobactam Ampicillin + Sulbactam = Unasyn Piperacillin + Tazobactam = Zosyn II. CLASSIFICATION OF ANTIMICROBIAL DRUGS 1. Cell-wall synthesis inhibitors & β-lactamase inhibitors 1.3 Cephalosporins 1st Generation 2nd Generation 3rd Generation 4th Generation Cephalothin Cefamandole Cefotaxime Cefepime Cephalexin Cefaclor Ceftazidime Cephradine Cefuroxime Cefoperazone axetil Cephapirin Cefonicid Ceftizoxime Cefadroxil Cefoxitin Ceftriaxone Cefazolin Cefotetan Cefixime Cefpodoxime II. CLASSIFICATION OF ANTIMICROBIAL DRUGS 1. Cell-wall synthesis inhibitors & β-lactamase inhibitors 1.3 Cephalosporins More effective Less effective G+ dec in g+ coverage 1st Gen inc in g- coverage 2nd Gen inc in CNS penetrn 3rd Gen inc in resistance to G- β -lactamase 4th Gen More effective Less effective II. CLASSIFICATION OF ANTIMICROBIAL DRUGS 1. Cell-wall synthesis inhibitors & β-lactamase inhibitors 1.3 Cephalosporins Cepha- Spectrum Organisms Clinical losporins of Activity Uses/Adverse Effects 1st Generation +++ - SPEcK – Staph, Strep, UTI, pneumonia; Proteus, E.coli, Klebsiella cephalothin is nephrotoxic 2nd Generation ++ - - HENSPEcK–Haemophilus Meningitis, Enterobacter, Neisseria, sinusitis, otitis Serratia, etc. media 3rd Generation + --- BPHENSPEcK- Borrelia, Lyme disease, Pseudomonas, etc. meningitis, gonorrhea 4th Generation ++ --- PENS – Pseudomonas, UTI, skin, Enterobacter, Staph, Strep pneumonia II. CLASSIFICATION OF ANTIMICROBIAL DRUGS 1. Cell-wall synthesis inhibitors & β-lactamase inhibitors 1.4 Carbapanems and Monobactams Carba- Spectrum of Organisms Clinical penems & Activity Uses/Adverse Mono- effects bactams Imipenem/ Aerobic & P. aeruginosa, B. For infections Cilastatin/ anaerobic g+ & fragilis but NOT resistant to other Meropenem g- organisms methicillin-resistant meds; high doses S.aureus (MRSA) cause seizures Aztreonam Aerobic g- rods P. Aeruginosa & For patients but NOT g+ or Serratia allergic to anaerobes penicillin; skin rashes, inc.SATs II. CLASSIFICATION OF ANTIMICROBIAL DRUGS 1. Cell-wall synthesis inhibitors & β-lactamase inhibitors 1.5 Others Others MOA Spectrum of Clinical Uses/Adverse effects Activity Vanco- Binds to D- G+, MRSA, Pseudomembra-nous colitis mycin alanyl-D- MRSE, (ONLY oral indication); serious alanine & Enterococcus g+ infectns resistant to β- stops faecalis, lactams; prophylaxis for pxs transpeptidn Clostridium with prosthetic heart valves; difficile ; NOT NEPHROTOXIC; hearing loss; for G- RED MAN SYNDROME-due to rapid IV infusion Cyclo- Antagonizes G+, G-, more 2nd line anti-TB drug; large serine D-alanine, for doses cause seizures; toxic stops alanine Mycobacteria racemase II. CLASSIFICATION OF ANTIMICROBIAL DRUGS 1. Cell-wall synthesis inhibitors & β-lactamase inhibitors 1.5 Others MOA Spectrum of Clinical Uses/Adverse Others Activity effects Isonia- Inhibition of zid mycolic acid Mycobacterium 4-drug regimen for PTB; (INH) synthesis tuberculosis RIPE – Rifampin, INH, (cell wall) Pyrazinamide, EMB - for new same + PTB taken for 6 months; Peripheral neuritis – due to vit B6 deficiency Hepatotoxic; hemolytic anemia EMB – optic neuritis (blurred vision, eye pain) II. CLASSIFICATION OF ANTIMICROBIAL DRUGS 2. ALTERATION OF CELL MEMBRANE PERMEABILITY (Bacteria) 2.1 Polymyxins (cationic peptide) EX: Colistin MOA: positively charged NH2 grps (like cationic detergents) disrupt phospholipid structure of the cell membrane CLINICAL USES: Topical for G- skin infections caused by Pseudomonas; nephrotoxic II. CLASSIFICATION OF ANTIMICROBIAL DRUGS 2. ALTERATION OF CELL MEMBRANE PERMEABILITY (Fungi) 2.2 ANTIFUNGAL DRUGS Polyenes Azoles Miscellaneous Amphotericin B Ketoconazole Flucytosine Nystatin Fluconazole Griseofulvin Itraconazole Miconazole Clotrimazole II. CLASSIFICATION OF ANTIMICROBIAL DRUGS 2. ALTERATION OF CELL MEMBRANE PERMEABILITY (Fungi) 2.2 ANTIFUNGAL DRUGS II. CLASSIFICATION OF ANTIMICROBIAL DRUGS 2. ALTERATION OF CELL MEMBRANE PERMEABILITY (Fungi) 2.2 ANTIFUNGAL DRUGS Polyenes Spectrum of Clinical Adverse Effects Activity Uses Amphotericin CHA – Candida, Systemic Nephrotoxic; B Cryptococcus fungal causes fever, neoformans, infections, chills; hypokalemia Coccidiodes sp, fungal leading to muscle Histoplasma sp, meningitis weakness Aspergillus Given IV,IT Nystatin Candida Vaginal Few reports candidiasis (topical) II. CLASSIFICATION OF ANTIMICROBIAL DRUGS 2. ALTERATION OF CELL MEMBRANE PERMEABILITY (Fungi) 2.2 ANTIFUNGAL DRUGS (block metabolism of lanosterol) Azoles Clinical Uses Adverse Effects Ketoconazole Against CHAB- GI effects: nausea & Blastomyces ; Oral vomiting Fluconazole Same; penetrates same CNS, oral & IV Itraconazole CHAB & Tinea Same infections, oral & IV Miconazole Same; topical & IV Few reports Clotrimazole Dermatophytes; topical Few reports II. CLASSIFICATION OF ANTIMICROBIAL DRUGS 2. ALTERATION OF CELL MEMBRANE PERMEABILITY (Fungi) 2.3 OTHER ANTIFUNGAL DRUGS Miscella- Clinical Uses Adverse Effects neous Flucytosine cryptococcal & candida Bone marrow depression (pyrimidine infections (tog. with (leukopenia & analog – 5- amphotericin B); oral; thrombocytopenia); hepatitis fluorouracil) narrow spectrum Griseofulvin Dermatophytes Headache, hepatotoxic, GI (ringworm- skin, hair, irritation nails); oral II. CLASSIFICATION OF ANTIMICROBIAL DRUGS 3. INHIBITION OF PROTEIN SYNTHESIS 30 S inhibitors: Aminoglycosides – bactericidal Tetracyclines - bacteriostatic 50 S inhibitors: Chloramphenicol – bacteriostatic Macrolides – bacteriostatic Lincosamides - bacteriostatic II. CLASSIFICATION OF ANTIMICROBIAL DRUGS 3. INHIBITION OF PROTEIN SYNTHESIS Amino- Tetra- Chloram- Macrolides Linco- glycosides cyclines phenicol samides Streptomycin Tetracycline Chloram- Erythromycin Clindamycin phenicol Gentamicin Doxycycline Clarithro- Lincomycin mycin Tobramycin Minocycline Azithromycin Amikacin Demeclo- cycline Netilmicin Oxytetra- cycline Neomycin Kanamycin II. CLASSIFICATION OF ANTIMICROBIAL DRUGS 3. INHIBITION OF PROTEIN SYNTHESIS- bind to 30S Amino- Clinical Uses Adverse Effects glycosides Streptomycin TB, bubonic plague, A – Allergic skin rxns streptococcal endocarditis Neomycin Gentamicin Pneumonia by M – neuroMuscular blockade; Pseudomonas aeruginosa, C.I. with myasthenia gravis UTI, IV, IM, topical Tobramycin I – Inactivated when physically mixed with β-lactams Amikacin N - Nephrotoxic Netilmicin O – Ototoxic, Optic nerve toxicity (streptomycin) Neomycin Bowel sterilization in prepn Ototoxicity: for surgery; skin infections strepto>amikacin>netilmicin Kanamycin For oral & topical Nephrotoxicity: neomycin>genta>strep II. CLASSIFICATION OF ANTIMICROBIAL DRUGS 3. INHIBITION OF PROTEIN SYNTHESIS- block binding of amino-acyl-t-RNA in mRNA complex Tetra- cyclines Clinical Uses Adverse Effects Tetracycline G+, G-, anaerobes Tooth & bone discoloration; Vibrio cholerae GI irritation Doxycycline Acne Fanconi syndrome – ingestion Chlamydia of expired drug Ureaplasma Vertigo, dizziness (Minocycline) Minocycline Mycoplasma CI: children < 8 yrs old Demeclo- Tularemia pregnant & lactating women cycline Borrelia burgdorferi Oxytetra- Rickettsia cycline VACUuM The BedRoom II. CLASSIFICATION OF ANTIMICROBIAL DRUGS 3. INHIBITION OF PROTEIN SYNTHESIS Chloramphenicol Clinical Uses Adverse Effects Bacteriostatic; Anemia (due to bone marrow Bactericidal for suppression) H. influenzae (children); Typhoid fever; anaerobic Gray Baby Syndrome – cyanosis, infections; rickettsial vomiting, green stools, vasomotor diseases in children & collapse pregnant women II. CLASSIFICATION OF ANTIMICROBIAL DRUGS 3. INHIBITION OF PROTEIN SYNTHESIS –binds to 23S rRNA of the 50S subunit Macrolides Clinical Uses Adverse Effects Clarithro- Aerobic G+ GI effects: nausea, mycin Pneumonia – vomiting, GI upset, Mycoplasma pneumoniae; diarrhea Pertussis – Bordetella Liver effects: Cholestatic Azithromycin pertussis; Legionnaire’s hepatitis disease – Legionella pneumophila Erythromycin Diptheria – Corynebacterium diphtheriae; chancroid – H. ducreyi; tetanus – Clostridium tetani II. CLASSIFICATION OF ANTIMICROBIAL DRUGS 3. INHIBITION OF PROTEIN SYNTHESIS – binds to 50S subunit Linco- Clinical Uses Adverse Effects samides Clindamycin G+ & Bacillus fragilis; Pseudomembranous prophylaxis in orthopedic colitis due to Clostridium surgery & treatment of difficile osteomyelitis; Skin rashes Acne; Lincomycin Pneumonia (Pneumocystis carinii) II. CLASSIFICATION OF ANTIMICROBIAL DRUGS 4. INHIBITION OF NUCLEIC ACID SYNTHESIS & REPLICATION Fluoroquinolones Rifampin Ciprofloxacin Rifampin Ofloxacin Norfloxacin Lomefloxacin Enoxacin Trovafloxacin Nalidixic acid (quinolone) II. CLASSIFICATION OF ANTIMICROBIAL DRUGS 4. INHIBITION OF NUCLEIC ACID SYNTHESIS & REPLICATION – inhibit DNA gyrase for DNA replication & transcription Fluoroquinolones Clinical Uses Adverse Effects G+, G- but NOT CNS effects: Ciprofloxacin anaerobes headache, dizziness UTI GI effects: nausea, Ofloxacin Prostatitis diarrhea Respiratory infections NOT for children – Norfloxacin cartilage damage Nosocomial infections Lomefloxacin GI infections – E. coli, Shigella, salmonella Enoxacin Chronic bone infections Trovafloxacin – Pseudomonas & S. aureus Nalidixic acid Diabetic foot infections (quinolone) II. CLASSIFICATION OF ANTIMICROBIAL DRUGS 4. INHIBITION OF NUCLEIC ACID SYNTHESIS & REPLICATION RIFAMPIN Clinical Uses Adverse Effects Tuberculosis (combined with : Red-orange colored MOA: Isoniazid secretions: sweat, binds to RNA Pyrazinamide tears, urine & feces polymerase and inhibits Ethambutol RIPE – new smear + PTB Flu-like syndrome – RNA chills, fever & myalgias synthesis for 1x or 2x weekly Meningitis intake Leprosy – Mycobacterium leprae (together with Dapsone) Legionnaire’s disease (tog. with erythromycin) II. CLASSIFICATION OF ANTIMICROBIAL DRUGS 5. INHIBITION OF ENZYME METABOLISM (Folate inhibitors) II. CLASSIFICATION OF ANTIMICROBIAL DRUGS 5. INHIBITION OF ENZYME METABOLISM (Folate inhibitors) Sulfonamides Trimethoprim Sulfisoxazole Trimethoprim Sulfamethoxazole Trimethoprim/sulfa- methoxazole Sulfadiazine Sulfamethizole Sulfasalazine Sulfadoxine Sulfacetamide Silver sulfadiazine Mafenide II. CLASSIFICATION OF ANTIMICROBIAL DRUGS 5. INHIBITION OF ENZYME METABOLISM (Folate inhibitors) Sulfonamides Clinical Uses Adverse Effects Sulfisoxazole G+, G-, bacteriostatic CRANK: UTI due to E. coli & Crystalluria Sulfamethoxazole Klebsiella but NOT (sulfadiazine) Sulfadiazine Pseudomonas- Rashes sulfamethoxazole Anemia Sulfamethizole Chlamydial infections- Nausea Sulfasalazine sulfacetamide Kernicterus Sulfadoxine Toxoplasmosis Stevens Johnson Nocardiosis – Sulfacetamide syndrome Nocardia Silver sulfadiazine (sulfisoxazole) CI: pregnant women, children < 2 mos old Mafenide (topical) Burn infections – Ag sulfadiazine II. CLASSIFICATION OF ANTIMICROBIAL DRUGS 5. INHIBITION OF ENZYME METABOLISM (Folate inhibitors) Trimethoprim Clinical Uses Adverse Effects Trimethoprim Recurrent UTIs Folate deficiency Bacterial prostatitis problems – anemia Trimethoprim/sulfa Gonorrhea Skin rashes -methoxazole Sinusitis/bronchitis Stevens-Johnson Pneumonia caused by syndrome Pneumocystis carinii GI effects: nausea, vomiting Acute otitis media Chancroid, shigellosis Typhoid fever II. CLASSIFICATION OF ANTIMICROBIAL DRUGS C. ANTIVIRAL DRUGS Rimantadine Interferons HOST CELL II. CLASSIFICATION OF ANTIMICROBIAL DRUGS C. ANTIVIRAL DRUGS Antiherpe- Antiretro- Antiretro- Antiretro- Other tic Drugs viral-NRTIs viral-NNRTIs viral- Antiviral Protease Drugs Inhibitors Acyclovir Zidovudine Nevirapine Indinavir Amantadine (AZT) Foscarnet Didanosine Delavirdine Saquinavir Rimantadine (ddI) Ganciclovir Zalcitabine Efavirenz Ritonavir Zanamivir (ddC) Idoxuridine Lamivudine Nelfinavir Oseltamivir (3TC) Vidarabine Abacavir Amprenavir Interferons Stavudine Ribavirin II. CLASSIFICATION OF ANTIMICROBIAL DRUGS C. ANTIVIRAL DRUGS – interfere/inhibit viral DNA polymerase & viral DNA replication Antiherpe- Clinical Uses Adverse effects tic Drugs Foscarnet Genital herpes, Nephro- & varicella (chickenpox), neurotoxic at high Herpes zoster doses (acyclovir) Ganciclovir (shingles) Bone marrow Cytomegalovirus/ suppression CMV retinitis in AIDS (ganciclovir) Idoxuridine patients (Foscarnet, Ganciclovir) Vidarabine For herpes, GIV acyclovir Acyclovir II. CLASSIFICATION OF ANTIMICROBIAL DRUGS C. ANTIVIRAL DRUGS – nucleoside analogs that can be incorporated into new viral directed DNA, terminating DNA chain Antiretro- Clinical Uses Adverse effects viral-NRTIs Zidovudine AIDS : CD4< 200 Anemia, headache, (AZT) cells/mL + presence of fatigue, peripheral Didanosine opportunistic infections neuropathy (ddI) RULE: CD4 normal but suspect HIV infectn, DO Zalcitabine NOT give anti-HIV med.; (ddC) CD4